1. Field of the Invention
The present invention generally relates to a screw fastener, featuring an additional, externally-threaded section that provides compression and/or fine adjustment apart from the typical threads, and, more particularly, that serves to improve the fastener by including multiple threaded portions for providing additional tightening and fine adjustment capabilities.
2. Description of the Related Art
In traditional nut and bolt structures, operations such as binding, compression, fine adjustment, and or measurement are controlled by the pitch of the threads on the nut and bolt. Typically, only one external thread and one internal thread, both with same pitch and direction are provided on these structures, thus limiting their usefulness suitability where compression or fine adjustment is needed.
While some nut and bolt assemblies may have multiple threaded sections, they also suffer from the following drawbacks:
1. Vulnerability to loss in the same manner as the conventional single piece nut and bolt designs; PA1 2. Absence of different thread orientations in each of the threaded sections which may allow loosening during vibration, and resonance frequency vibration in particular; and PA1 3. Absence of consideration with regard to the direction of rotation of the threads which limits the scope of application.
In order to provide features that save labor on the part of the user, and to allow for compression and fine adjustment capabilities so as to expand the scope of applications, a novel composite nut and bolt design is disclosed here.